Just me then. Thanks for checking, anyway.
When I turn UAC back on (minimum level) and reboot, I get the following in this sequence:
1. Program Manager tells me that rainlendar2.ini is not writeable.
2. I get a "Rainlendar2 has stopped working" message:
Problem Event Name: BEX
Application Name: Rainlendar2.exe
Application Version: 18.104.22.168
Application Timestamp: 513cc9d3
Fault Module Name: StackHash_b932
Fault Module Version: 0.0.0.0
Fault Module Timestamp: 00000000
Exception Offset: e850c045
Exception Code: c0000005
Exception Data: 00000008
OS Version: 6.0.6002.2.2.0.768.3
Locale ID: 2057
Additional Information 1: b932
Additional Information 2: 08394b3e941a98bd45a881bbe6e3d462
Additional Information 3: 8fff
Additional Information 4: 3da206f00c96723341e9a9aaa754851f
3. I get a pop-up DEP message about Rainlendar2 in the bottom right.
I've just tried resetting some system settings to default in case it's something obscure, but I get the same issue on reboot.
I'm not sure what to try next. Yes, I would like Windows 7 or even 8 (maybe) but it's a matter of cost and hanging on to some very useful installed programs.
I'll turn UAC off again.
Thanks again for investigating, Rainy.